Butadiene Rubber Compounds Research Articles

From Nanoscale to Macroscale Characterization of Sulfur-Modified Oxidized Carbon Nanotubes in Styrene Butadiene Rubber Compounds.

The homogeneous dispersion of carbon nanotubes (CNTs) in a rubber matrix is a key factor limiting their amazing potential. CNTs tend to agglomerate into bundles due to van der Waals interactions. To overcome this limitation, CNTs have been surface-modified with oxygen-bearing groups and sulfur. Using atomic force microscopy (AFM) techniques, a deep nanoscale characterization of the morphology, the degree of dispersion of the CNTs in the styrene butadiene rubber (SBR) matrix, and the thickness of the interfacial layer was carried out in this study. In this context, the results from nanoscale characterization showed that the thermal oxidation-sulfur treatment leads to a composite with better dispersion in the matrix, as well as a thicker interfacial layer, indicating a stronger filler-rubber interaction. The second part of this work focused on the macroscale results, such as the Payne effect, vulcanization curves, and mechanical properties. The Payne effect, vulcanization curves, and mechanical properties confirmed the lower reinforcing effect observed in the case of the chemical oxidation treatment because, on the one hand, this composite showed the highest agglomeration of CNTs after the acid treatment. On the other hand, the presence of acid residues provoked the absorption of basic accelerators on the surface of the CNTs.

Nitroxide-Functionalized Green Silica with Radical Capturing Potential as a Filler in the Styrene–Butadiene Rubber Compound

Nitroxide-Functionalized Green Silica with Radical Capturing Potential as a Filler in the Styrene–Butadiene Rubber Compound

Modeling the rheological behavior of silica filled rubber compounds

The rheological behavior of styrene–butadiene rubber (SBR) compounds filled with silica is investigated as a function of silica volume fraction. To predict the mechanical response, a continuum model for entangled polymer melts filled with nanoparticles is herein introduced. This model is capable of describing the rheological response in both the linear and nonlinear viscoelastic regimes in the context of non-equilibrium thermodynamics to guarantee its thermodynamic admissibility. The constitutive model describes the polymer nanocomposite melts at a mesoscopic level of description by considering the conformation tensor between successive entanglement points, and the orientation tensor for the, in general, spheroidal nanoparticles that describes their average orientation. Evolution equations are developed for nanoparticles with an arbitrary shape but are eventually specified to the case of spherical ones. The multimode version of the new constitutive model provides a very accurate prediction of the rheological behavior of the processability range of SBR/silica nanocomposites. Thus, the new model is a tool able to provide answers to the several difficulties that rubber-producing manufacturers face when processing rubber compounds.

Oleamide as palm-oil based substance for silica-loaded styrene butadiene rubber compound: The cure and crosslinks behaviors

Oleamide is an amide substance that can be made from oleic acid of palm oil with urea. Since palm oil is a type of agriculture product, the oleamide is an environment-friendly or (semi) sustainability additive for rubber compounding. In this research, the oleamide was applicated in making the silica-loaded of synthetic rubber, styrene butadiene rubber (SBR) at an opened two-roll mills. In this study, effects of oleamide incorporations on cure and level of crosslinks of silica-SBR compounds were observed. The SBR was loaded with thirty parts per hundred (phr) of SBR and, they and other compounding substances i.e., stearic acid, zinc oxide, antioxidant, accelerator, antioxidant and sulphur were compounded with semi-efficient formulation. The oleamide was incorporated with a series of amounts from 2 to 8 phr. It was found that the oleamide incorporations exhibited faster times in cure and scorching; The oleamide also exhibited a lifting up of delta torque and crosslinks level for the silica-SBR compound. The 2 phr incorporation of oleamide to silica-SBR was the optimum concentration which exhibited the greatest delta torque and level of crosslinks of silica-SBR vulcanizate.

Determination of the crosslink density of silica-filled styrene butadiene rubber compounds by different analytical methods

AbstractThe crosslink density of rubber compounds has a great effect on the properties of the final product. For this reason, a suitable characterization method is required to understand and optimize the final performance of rubber materials. Four different experimental techniques were used to determine the crosslink density of silica-filled styrene butadiene rubber composites: equilibrium swelling experiments, stress–strain measurements using the Mooney–Rivlin theory, freezing point depression temperature tests and Temperature Scanning Stress Relaxation (TSSR) measurements. The evaluation of these different techniques shows that the results obtained follow a similar trend for all four methods. The results from the Mooney-Rivlin and TSSR measurements correlate the best. These two techniques are the least affected by the presence of fillers and are the less time-consuming ones. Furthermore, they also show the best correlation with the mechanical properties of the studied compounds.

Development of 3D printed human brain models using thermoplastic Polyurethane/Rubber blends for anatomy teaching promoting kinesthetic learning purposes

Kinesthetic appreciation of anatomy models serves to activate a concrete sensory experience that enhances 3D visuospatial mental mapping of anatomical structures. However, most commercially available plastic anatomy models are costly and do not provide tactile sensation similar to the organ or structures. Polymeric materials have been used widely in additive manufacturing to produce human brain models, however, none of the models resembles accurate feeling. The aim of this study is to produce 3D printed anatomical models using customized soft 3D printing filament from thermoplastic Polyurethane (TPU) and two types of rubber, which are ethylene propylene diene monomer (EPDM) and styrene butadiene rubber (SBR) compounds. Actual human brain MRI scans are used to form 3D-printed anatomy models. The MRI image obtained was in DICOM format, exported into 3D slicer software for specific brain parts extraction (whole brain, brain ventricles, circle of Willis, and dural venous sinuses), and converted into STL format for 3D printing. For material processing, the blending of TPU/EPDM and TPU/SBR were successfully fabricated using an internal mixer (Haake) and extruded into filament using a single screw extruder with the aid of a filament winder. The human brain model was then printed using 3D Printer (Ender 3). It was found that all TPU blends were able to be printed into brain anatomy models but the properties of the materials were greatly affected by rubber types and compositions of the added fillers. The addition of more than 30% of the fillers gave difficulties in processing, probably due to inconsistent viscosity that led to phase separation.

Experimental separation of the onset of slip and sharkskin melt instabilities during the extrusion of silica-filled, styrene–butadiene rubber compounds

The flow curves of polymers often reveal the onset of melt instabilities such as sharkskin, stick–slip, or gross melt fracture, in order of increasing shear rates. The focus of this work lies in the application of the Göttfert sharkskin option to the investigation of flow curves of styrene-butadiene rubber (SBR) compounds. The sharkskin option consists of highly sensitive pressure transducers located inside a slit die of a capillary rheometer. This tool allows the detection of in-situ pressure fluctuation characteristics of different melt instabilities. It is shown that the change of slope of the transition region in the flow curves is only linked to slip. Dynamic Mechanical Analysis (DMA) measurements furthermore show that the shear rate at which the change of slope can be observed shows the same temperature dependency as the viscous and elastic properties of the compounds.

Nonlinear viscoelastic behavior and their time-temperature superposition for filled styrene butadiene rubber compounds and vulcanizates

The nonlinear viscoelastic behavior of rubber composites is of great practical importance in their processing as well as the application. In this paper, nonlinear viscoelastic behavior for vulcanized and unvulcanized filled styrene butadiene rubbers (SBR), SBR/carbon black (CB) composites, were mainly investigated. Besides the conventional Payne effect, frequency (ω) sweep tests at different strains (linear and nonlinear viscoelastic regions) were performed to get more information about viscoelastic response, especially in nonlinear region that close to actual driving conditions. Conductivity synchronization test was also operated to explore the evolution of CB agglomerates. It reveals that the filler network structure recovers slowly but the rubber network recovers rapidly during an increasing and decreasing strain sweep cycle. At large strain, rheological parameters of vulcanizates change significantly with increasing ω. A pseudomaster curve based on the ω sweep at large strain and different temperature can be obtained both for compounds and vulcanizates, indicating that the time-temperature superposition is also applicable to the nonlinear viscoelastic behavior. Similar linear and nonlinear viscoelastic behaviors of filled vulcanizates to that of unfilled vulcanizates demonstrate the same mechanism of viscoelastic response. The loss modulus peak of filled vulcanizates primarily comes from the Rouse movement of rubber chains between crosslinking points. Under large strain, the strain amplication effect of particles hardly influence the characteristic relaxation time of Rouse movement between crosslinking points.

Constructing a fine dispersion and chemical interface based on an electrostatic self-assembly and aqueous phase compound in GO/SiO2/SBR composites to achieve high-wear resistance in eco-friendly green tires

The hazard to the ecosystem caused by rubber microparticles generated from tire abrasion has been a constant concern. Therefore, to protect this ecosystem, the development of a tire tread with high abrasion resistance is especially significant. Herein, γ-aminopropyltriethoxysilane (APTES) was used to modify graphene oxide (GO) and silica (SiO2) to obtain GO and SiO2 with positive charges (NG and NS). Furthermore, NG and NS were electrostatically self-assembled by using maleic anhydride (MAH) hydrolysis, thereby obtaining composite particles (NG-NS) with “bridged structures”. Also, the NG-NS/styrene butadiene rubber (SBR) compounds possessing fine dispersion of NG-NS were prepared by the aqueous compounding method. During the crosslinking process, the vinyl groups in NG-NS reacted with the vinyl groups of the SBR molecule chains, thus forming strong chemical interfacial interactions between the NG-NS and rubber macromolecules. Compared with an SiO2/SBR composite, the 300 % modulus, tensile strength, abrasion resistance of the NG-NS/SBR composite were improved by 125 %, 122 %, 83.3 %, respectively. Compared with a GO/SiO2/SBR composite, heat build-up in the NG-NS/SBR was decreased by 8.2 °C.

Influence of the Polarity of the Plasticizer on the Mechanical Stability of the Filler Network by Simultaneous Mechanical and Dielectric Analysis.

Four styrene butadiene rubber (SBR) compounds were prepared to investigate the influence of the plasticizer polarity on the mechanical stability of the filler network using simultaneous mechanical and dielectric analysis. One compound was prepared without plasticizer and serves as a reference. The other three compounds were expanded with different plasticizers that have different polarities. Compared with an SBR sample without plasticizer, the conductivity of mechanically unloaded oil-extended SBR samples decreases by an order of magnitude. The polarity of the plasticizer shows hardly any influence because the plasticizers only affect the distribution of the filler clusters. Under static load, the dielectric properties seem to be oil-dependent. However, this behavior also results from the new distribution of the filler clusters caused by the mechanical damage and supported by the polarity grade of the plasticizer used. The Cole–Cole equation affirms these observations. The Cole–Cole relaxation time and thus, the position of maximal dielectric loss increases as the polarity of the plasticizer used is also increased. This, in turn, decreases the broadness parameter implying a broader response function.

Evaluation of lignin as potential green filler in an optimally designed solution grade styrene–butadiene rubber (SSBR) based tyre tread compound

ABSTRACT In this study, solution grade styrene–butadiene rubber (SSBR) compound was prepared by partial replacement of silica with lignin. The compounds were designed and optimised using an L9 orthogonal array (using Taguchi method) targeting ‘magic triangle’. Cure rate index (CRI), reinforcement index (RI) and hysteresis loss (loss tangent at 60°C) were considered as the responses. Thermo-gravimetric analysis and Differential scanning calorimeter is used to assess thermal degradation and intramolecular reactivity of lignin. Morphological analysis of the composites has instituted the fact that above 20% replacement of synthetic silica by lignin results in re-agglomeration of filler particles due to inferior dispersion. Response analysis through ANOVA coupled with an experimental study on physico-mechanical and dynamic-mechanical properties has manifested that SSBR with 58% vinyl content with 40:10 silica: lignin compounded at 160°C with 10% silane coupling agent (SCA) with respect to silica at factorial levels furnished a ‘magic triangle’ optimised tyre tread compound.

Combinations of dual-function azide-containing crosslinkers with C-H insertion capabilities for polymeric elastomers with improved adhesion properties

The utilization of the noncatalytic C-H insertion capability of the nitrene intermediate of azide-containing compounds is proposed in this study for the clean fabrication of polymer-inorganic functional hybrid materials with elasticity and adhesion capabilities. For this purpose, a combination of dual-function azide-based crosslinkers composed of azidosilane (6-azidosulfonylhexyltriethoxysilane, AS) and diazide-based crosslinkers [tri(ethylene glycol)diazidoformate, GDAF] is attempted. AS affords good adhesion capability of polymer materials to OH-containing inorganic substrate/fillers, while GDAF undergoes a simultaneous C-H insertion reaction with polymer chains in bulk, affording enough crosslinking sites to improve elasticity. Through adjustments of the compositions and curing conditions, the styrene butadiene rubber compound with the proposed combination of crosslinkers exhibits good mechanical properties and excellent elasticity, as demonstrated by the low tension set value. The compound also exhibits improved adhesion capability on OH-containing silica, quartz and polyimide films, providing functional hybrid materials with an ideal combination of elasticity and adhesion capabilities suitable possibly for cutting-edge applications.

Nanodiamond—Carbon Black Hybrid Filler System for Demanding Applications of Natural Rubber—Butadiene Rubber Composite

The objective of the study was to investigate the effect of the partial replacement of carbon black (CB) by nanodiamonds (NDs) on the vulcanization, mechanical and dynamic properties of a natural rubber—butadiene rubber compound, a typical elastomer compound found in several applications (the tire and mining industry, for example). A studied hybrid filler system resulted in a 28% increase in tensile strength and 29% increase in 300% modulus at low ND loadings even though the total weight fraction of the filler system was kept constant at 25 parts per hundred rubber. The hybrid filler system improved dispersion of both fillers as was proven by scanning electron microscopy and the Payne effect study. In addition, the replacement of 2.5 and 5 phr CB by NDs resulted in 62% improvement in wear resistance. The DMA study showed that a certain ND-CB filler combination has a positive effect on tire properties such as wet grip and rolling resistance.

Long-term ISO 23936-2 sweet oil ageing of HNBR

A hydrogenated nitrile butadiene rubber (HNBR) compound is subjected to ageing in a simulated oil and gas environment in accordance with ISO 23936-2 standard at two elevated temperatures (130°C and 150°C) for a period of up to 9 months. Shore D hardness, thermal expansion, dynamic mechanical analysis (DMA), Fourier transform infrared (FTIR) spectroscopy, compression and compression set (CS) measurements are made before and after the chemical exposure. The hardness, modulus at short times, degree of relaxation and CS increases while the coefficient of thermal expansion in HNBR tends to decrease with ageing time and temperature. Temperature is shown to impose a greater effect on the properties than ageing time in the experiment. The elastic modulus at low frequencies of cyclic deformation (or the equilibrium modulus in stress relaxation) has a more complicated relationship with ageing time at 150°C. It sharply increases in the first stage of ageing and then decreases later with further exposure which suggests that chain scission dominates in the later stages of hydrocarbon ageing. In contrast with the other materials, the most severely aged HNBR exhibits a much higher glass transition temperature of ≈+70°C manifesting in a very high stiffness at ambient temperature and a low thermal expansion coefficient. This effect is attributed to a dramatic change in the chemical structure of aged HNBR, i.e. complete modification of C≡N groups to amide groups yielding the growth of Tg and the corresponding variation in macroscopic properties. These results are also qualitatively evaluated in the context of potential sealing applications of the material.

Impact Modified Polyvinyl Chloride Based Thermoplastic Elastomers: Effect of Nitrile Butadiene Rubber and Graphene Oxide Loading

A new thermoplastic elastomer with improved impact and tensile properties was produced through melt blending of graphene oxide filled nitrile butadiene rubber (NBR-GO) and polyvinyl chloride (PVC) without the addition of plasticisers and thermal stabilisers. Nitrile butadiene rubber (NBR) compounds, with and without graphene oxide (GO) are prepared through latex compounding method and cured, prior to blending with PVC. The effect of NBR and NBR-GO loading on the process-ability and physico-mechanical properties of PVC blends were evaluated. The addition of NBR and NBR-GO improved tensile strength (TS), impact strength and swelling resistance of PVC. Addition of NBR also increased the stiffness of PVC due to higher elasticity of NBR as compared to PVC. Optimum impact strength, TS and swelling resistance was achieved with the addition of 10 wt. % NBR-GO. Good miscibility between NBR and PVC, and additional reinforcement by GO is responsible for enhancement of impact and TS. NBR-GO showed greater miscibility in PVC as compared to NBR as proven by morphological observation under scanning electron microscope. Morphological observation reveals that micro-cracks formation on PVC/30NBR surface which is responsible for low impact, tensile and swelling properties as compared to PVC/30NBR-GO composite.

Cross‐linking and foaming behavior of elastomers with water based blowing agents

AbstractPhysiologically hazardous chemical blowing agents are state of the art for the foaming of extruded rubber profiles. Water is a potential alternative to these blowing agents and is incorporated into rubber compounds in the form of water‐loaded hygroscopic substances such silica or hydrates. To achieve an optimum foaming result, the water desorption and cross‐linking reaction has to be coordinated. Studies of the foaming behavior in the salt bath of the Sponge Rubber Analyzer show, that the density of an ethylene propylene diene monomer (EPDM) rubber compound is reduced to about 60% and a nitrile butadiene rubber (NBR) compound to approximately 70%. The low reference densities of chemically foamed EPDM of 30% and NBR of 45% are not achieved. This is attributed to the premature foaming when using water‐loaded silica as blowing agent. Due to the low resistance of the rubber matrix, large cells are formed by coalescence, which collapse at low cross‐linking densities. Investigations of the cross‐linking behavior of EPDM and NBR with water‐loaded silica as blowing agent state, that the cross‐linking density is reduced to about 65% for EPDM and 50% for NBR when water is present. Furthermore, the incubation time is shortened by inhibition of the CBS retarder in the cross‐linking system of the NBR. However, this is not sufficient to fix the foamed cells.

Road to Increased Tire Sustainability: Carbon Black Replacement in Styrene Butadiene Rubber Compounds using Eco-Friendly Fillers

Road to Increased Tire Sustainability: Carbon Black Replacement in Styrene Butadiene Rubber Compounds using Eco-Friendly Fillers

Chemically modified soybean oils as plasticizers for silica-filled e-SBR/Br compounds for tire tread applications

Silica-filled styrene butadiene rubber (SBR)/butadiene rubber (BR) compounds plasticized with mineral oils are mainly used to produce green tire treads. Previous works have demonstrated that the partial replacement of naphthenic oil (ONAF) by bio-based oils can provide processing and performance improvements for rubber compounds, along with environmental benefits. In this study, two modified soybean oils (esterified, OEST or esterified and epoxidized, OEPX) were investigated with the aim of evaluating the complete replacement of ONAF and determining whether the chemical properties of the oils affect the performance of silica-filled E-SBR/BR compounds, using the compound with ONAF as a reference. The physical properties, curing characteristics, morphology, and dynamic mechanical behavior were evaluated. The use of the modified soybean oils decreased the optimal cure time while increasing the crosslink density and the abrasive wear resistance. Further, the compounds with both modified soybean oils showed a good balance of mechanical properties. The modified soybean oils decreased the glass transition temperature of the rubber compounds, thus acting as true plasticizers. At 0°C, the tan δ value of E-SBR/BR/OEPX increased relative to that of E-SBR/BR/ONAF, whereas at 60°C, the values of the compounds with both modified soybean oils showed slight increases. The tan δ values reveal that compared with E-SBR/BR/ONAF, E-SBR/BR/OEPX has better wet grip and a similar rolling resistance, whereas E-SBR/BR/OEST has a higher rolling resistance. Thus, both modified soybean oils can fully replace ONAF and appear to be extremely attractive plasticizers for use in silica-filled E-SBR/BR compounds employed as green tire treads for passenger cars.

Effect of Sulfur Variation on the Vulcanizate Structure of Silica-Filled Styrene-Butadiene Rubber Compounds with a Sulfide-Silane Coupling Agent.

The vulcanizate structure of filled compounds is affected by filler–rubber interactions (FRI) and the chemical crosslink density (CCD) of the matrix rubber. In particular, in filled compounds using a silica–silane system, FRIs due to silica–rubber coupling are a major influencing factor for the vulcanizate structure and physical properties. In this study, the effect of sulfur variation on the vulcanizate structure of silica-filled solution styrene–butadiene rubber compounds using a sulfide–silane coupling agent was studied. The vulcanizate structure according to sulfur variation was quantitatively analyzed using the swelling test and Flory–Rehner and Kraus equations. As the sulfur content increased, both FRI and the CCD increased, and it was confirmed that sulfur variation influenced the silica–rubber coupling efficiency through increased FRI. In addition, field emission scanning electron microscope images showed that increased FRI contributed to improvements in silica dispersion, abrasion resistance, and energy loss characteristics.

Disinfection of gloved hands during the COVID-19 pandemic

BackgroundDisinfection of gloves can be used during a pandemic situation when performing various procedures on the same patient or when removing personal protective equipment. If performing glove disinfection, there is a need to check the compatibility of gloves with the disinfectant product used.AimTo test the resistance of nitrile gloves to various disinfectant solutions.MethodsOne hundred percent powder-free nitrile gloves, composed of nitrile butadiene rubber compounds, were exposed to various disinfectants to analyse resistance. The seven most commonly used disinfectant solutions in the healthcare field were selected for testing. The effects of each disinfectant were analysed in comparison with the control group (untreated glove). For tensile testing, the thickness of each test specimen was measured with a micrometer.FindingsBleach solution decreased the breaking load of gloves, although to a lesser extent than disinfectants that contained ethanol.ConclusionDisinfectants that contain alcohol decrease the breaking load of nitrile gloves.